Otterbox defender and back scratches???

I just bought a used 3GS from a guy that upgraded to the 4. He took VERY good care of it and it looks BRAND NEW!
He included an Otterbox Defender. I have ordered a full body film to protect the back from scratches but I won't get it for another few days. Since the back is MINT I'm really worried about it getting scratched!

Anyone that has used the Defender, will the inside of the Defender scratch the back of my iPhone? If not, I'll put the phone in it right away! If it will, I'll just wait until the film comes in before I pop my SIM in the phone :S

PS I did try searching but couldn't find anything with regards to whether or not the case will scratch the phone.